KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 201 insertions, 0 deletions

diff --git a/arch/mips/jazz/setup.c b/arch/mips/jazz/setup.c
new file mode 100644
index 000000000..d21e5d441
--- /dev/null
+++ b/arch/mips/jazz/setup.c
@@ -0,0 +1,201 @@
+/*
+ * Setup pointers to hardware-dependent routines.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1996, 1997, 1998, 2001, 07, 08 by Ralf Baechle
+ * Copyright (C) 2001 MIPS Technologies, Inc.
+ * Copyright (C) 2007 by Thomas Bogendoerfer
+ */
+#include <linux/eisa.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/console.h>
+#include <linux/platform_device.h>
+#include <linux/serial_8250.h>
+#include <linux/dma-mapping.h>
+#include <linux/pgtable.h>
+
+#include <asm/jazz.h>
+#include <asm/jazzdma.h>
+#include <asm/reboot.h>
+#include <asm/tlbmisc.h>
+
+extern void jazz_machine_restart(char *command);
+
+static struct resource jazz_io_resources[] = {
+	{
+		.start	= 0x00,
+		.end	= 0x1f,
+		.name	= "dma1",
+		.flags	= IORESOURCE_IO | IORESOURCE_BUSY
+	}, {
+		.start	= 0x40,
+		.end	= 0x5f,
+		.name	= "timer",
+		.flags	= IORESOURCE_IO | IORESOURCE_BUSY
+	}, {
+		.start	= 0x80,
+		.end	= 0x8f,
+		.name	= "dma page reg",
+		.flags	= IORESOURCE_IO | IORESOURCE_BUSY
+	}, {
+		.start	= 0xc0,
+		.end	= 0xdf,
+		.name	= "dma2",
+		.flags	= IORESOURCE_IO | IORESOURCE_BUSY
+	}
+};
+
+void __init plat_mem_setup(void)
+{
+	int i;
+
+	/* Map 0xe0000000 -> 0x0:800005C0, 0xe0010000 -> 0x1:30000580 */
+	add_wired_entry(0x02000017, 0x03c00017, 0xe0000000, PM_64K);
+	/* Map 0xe2000000 -> 0x0:900005C0, 0xe3010000 -> 0x0:910005C0 */
+	add_wired_entry(0x02400017, 0x02440017, 0xe2000000, PM_16M);
+	/* Map 0xe4000000 -> 0x0:600005C0, 0xe4100000 -> 400005C0 */
+	add_wired_entry(0x01800017, 0x01000017, 0xe4000000, PM_4M);
+
+	set_io_port_base(JAZZ_PORT_BASE);
+#ifdef CONFIG_EISA
+	EISA_bus = 1;
+#endif
+
+	/* request I/O space for devices used on all i[345]86 PCs */
+	for (i = 0; i < ARRAY_SIZE(jazz_io_resources); i++)
+		request_resource(&ioport_resource, jazz_io_resources + i);
+
+	/* The RTC is outside the port address space */
+
+	_machine_restart = jazz_machine_restart;
+
+	add_preferred_console("ttyS", 0, "9600");
+}
+
+#ifdef CONFIG_OLIVETTI_M700
+#define UART_CLK  1843200
+#else
+/* Some Jazz machines seem to have an 8MHz crystal clock but I don't know
+   exactly which ones ... XXX */
+#define UART_CLK (8000000 / 16) /* ( 3072000 / 16) */
+#endif
+
+#define MEMPORT(_base, _irq)				\
+	{						\
+		.mapbase	= (_base),		\
+		.membase	= (void *)(_base),	\
+		.irq		= (_irq),		\
+		.uartclk	= UART_CLK,		\
+		.iotype		= UPIO_MEM,		\
+		.flags		= UPF_BOOT_AUTOCONF,	\
+	}
+
+static struct plat_serial8250_port jazz_serial_data[] = {
+	MEMPORT(JAZZ_SERIAL1_BASE, JAZZ_SERIAL1_IRQ),
+	MEMPORT(JAZZ_SERIAL2_BASE, JAZZ_SERIAL2_IRQ),
+	{ },
+};
+
+static struct platform_device jazz_serial8250_device = {
+	.name			= "serial8250",
+	.id			= PLAT8250_DEV_PLATFORM,
+	.dev			= {
+		.platform_data	= jazz_serial_data,
+	},
+};
+
+static struct resource jazz_esp_rsrc[] = {
+	{
+		.start = JAZZ_SCSI_BASE,
+		.end   = JAZZ_SCSI_BASE + 31,
+		.flags = IORESOURCE_MEM
+	},
+	{
+		.start = JAZZ_SCSI_DMA,
+		.end   = JAZZ_SCSI_DMA,
+		.flags = IORESOURCE_MEM
+	},
+	{
+		.start = JAZZ_SCSI_IRQ,
+		.end   = JAZZ_SCSI_IRQ,
+		.flags = IORESOURCE_IRQ
+	}
+};
+
+static u64 jazz_esp_dma_mask = DMA_BIT_MASK(32);
+
+static struct platform_device jazz_esp_pdev = {
+	.name		= "jazz_esp",
+	.num_resources	= ARRAY_SIZE(jazz_esp_rsrc),
+	.resource	= jazz_esp_rsrc,
+	.dev = {
+		.dma_mask	   = &jazz_esp_dma_mask,
+		.coherent_dma_mask = DMA_BIT_MASK(32),
+	}
+};
+
+static struct resource jazz_sonic_rsrc[] = {
+	{
+		.start = JAZZ_ETHERNET_BASE,
+		.end   = JAZZ_ETHERNET_BASE + 0xff,
+		.flags = IORESOURCE_MEM
+	},
+	{
+		.start = JAZZ_ETHERNET_IRQ,
+		.end   = JAZZ_ETHERNET_IRQ,
+		.flags = IORESOURCE_IRQ
+	}
+};
+
+static u64 jazz_sonic_dma_mask = DMA_BIT_MASK(32);
+
+static struct platform_device jazz_sonic_pdev = {
+	.name		= "jazzsonic",
+	.num_resources	= ARRAY_SIZE(jazz_sonic_rsrc),
+	.resource	= jazz_sonic_rsrc,
+	.dev = {
+		.dma_mask	   = &jazz_sonic_dma_mask,
+		.coherent_dma_mask = DMA_BIT_MASK(32),
+	}
+};
+
+static struct resource jazz_cmos_rsrc[] = {
+	{
+		.start = 0x70,
+		.end   = 0x71,
+		.flags = IORESOURCE_IO
+	},
+	{
+		.start = 8,
+		.end   = 8,
+		.flags = IORESOURCE_IRQ
+	}
+};
+
+static struct platform_device jazz_cmos_pdev = {
+	.name		= "rtc_cmos",
+	.num_resources	= ARRAY_SIZE(jazz_cmos_rsrc),
+	.resource	= jazz_cmos_rsrc
+};
+
+static struct platform_device pcspeaker_pdev = {
+	.name		= "pcspkr",
+	.id		= -1,
+};
+
+static int __init jazz_setup_devinit(void)
+{
+	platform_device_register(&jazz_serial8250_device);
+	platform_device_register(&jazz_esp_pdev);
+	platform_device_register(&jazz_sonic_pdev);
+	platform_device_register(&jazz_cmos_pdev);
+	platform_device_register(&pcspeaker_pdev);
+
+	return 0;
+}
+
+device_initcall(jazz_setup_devinit);